1. Field of the Invention
This invention relates to an improved hip prosthesis.
Total prostheses of the hip that are ordinarily made are the friction seat between the spherical part replacing the head of the femur and its housing implanted in the pelvis of the patient. Because of this friction and regardless of the materials used, a wear occurs that necessitates the replacement of all or part of the prosthesis at the end of a certain time.
To eliminate this drawback, French patent 2,261,743 describes a prosthesis whose oscillation pin mounted on a bearing is inclined 20.degree. in relation to the horizontal, this arrangement making it possible during walking to have only a single oscillation movement around this pin and therefore to eliminate the wear between the spherical head and its housing since their relative movement then becomes zero.
However, if the friction between the spherical head and its housing has been eliminated, the problem has been shifted to the level of the bearing which is composed of a pin pivoting in a cylindrical housing and of a row of balls making possible the axial hold of the unit.
During the operation of the prosthesis, a wear by friction will develop between the pin and its housing necessitating, in time, a new operation.